Yet another D5 conversion

[Zabco]

After watching a couple of Bruder D5 bulldozers in action at the recent Central Plains Mini Truckers meet in Lebanon, IN I decided I needed to make one also. I reviewed several build articles on this and other forums to see how others did this converison and get an idea of what I would need to acquire in the way of parts. For the most part my conversion was similar to others in that I used a Tamiya 70168 double gearbox and a Sabertooth 2x5RC controller. I won't review the process of installing these parts as others have detailed steps in their builds.

When I do one of these conversions one of my main goals is to have the final product look as much like the original toy as possible. In looking at all the videos and photos of other D5 conversions there were two areas in particular where apperances were altered that kind of bothered me and that I wanted to see if I could address. The first of these was the drive sprocket.

In researching this build it quckly became apparent that the original drive sprocket simply does not work well when it becomes powered. As soon as the tracks start to streatch just a little bit, the original sprockets start slipping badly. There have been a number of ways to address this issue from installing screws in the sprocket to replacing them with 3d printed sprockets with longer teeth. There are several versions of 3d printable sprockets available on the internet and I down loaded all that I could find and printed them out to try. I wasn't really happy with the apperance of any of them. Sitting in the shop one afternoon looking at the D5 it occurred to me that there was a gap between the 'gear' portion of the sprocket and the 'hub' portion. This means there has to be a narrower rib between the two parts. What if you cut off the gear portion leaving the rib. Then you could design and print a new gear and using the rib as an index to keep everyting aligned, attach the new gear to the original hub? Since most of the new gear is buried inside the track it really can't be seen and the sprocket would look pretty much exactly like the original.

Mounted the sprockets up in a lathe and turned off the entire 'gear' portion being careful to leave the rib intact.

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This could probably also be done by chucking the sprockets up carefully in a drill chuck to spin them and using a file to remove the teeth if a lathe is not available. A before and after view of removing the sprockets.

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I went through several versions trying different lengths and shapes before finding a combination that seemed to work well. Really nice thing about 3d printing, it's quick and easy to make a change and make a new part.

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Printed out a couple of the final version and attached them to the original hubs. The new sprockets were sized to be a friction fit on the hubs and to make sure they would'nt come loose I glued them in place with Plastruct Plastiweld. Plastiweld by the way works well on most of the plastic used by Bruder. Photo of the completed sprocket assemblies.

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And mounted on the D5 with the track in place.

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Upon final assembly I painted the new sprocket yellow and from a couple of feet away you really can't tell the sprockets are not the originals. By the way, does anyone know of a brand/name of a yellow that really matches the yellow used by Bruder? Not yet been able to come up with a match that I'm really happy with.